1. Field of the Invention
This invention relates generally to door locks, and pertains more particularly to accessory devices for preventing access to the keyhole of a doorknob.
2. Description of the Prior Art
So-called key-in-knob locks are commonly employed in the doors to rooms of hotels and motels. While various arrangements are provided for the protection of the occupant when in his or her room, such as dead bolt locks and chains, a problem exists with respect to unauthorized entry from the outside when the occupant is not in the room. It is relatively easy for a previous user of the room to have a duplicate key made and return to that room at a later time with the thought of perpetrating a burglary. There are other reasons for not wanting a person to be able to unlock the key-in-knob lock when the traveler is not occupying the room, such as when sightseeing or making business visits. In this regard, the renter of the hotel or motel room may very well have valuable equipment therein that must be safeguarded from maids and other hotel personnel when the renter is away.
A number of patents have been granted for various protective devices as far as doorknobs having keyholes therein are concerned. One such patent is U.S. Pat. No. 3,245,240 issued on Apr. 12, 1966 to William E. De Forrest for "Knob Protector". Another such device is disclosed in U.S. Pat. No. 3,636,742 granted on Jan. 25, 1972 to Gerrel B. Raney for "Lock-Out Key Holder". Although it is not known to me whether such prior art devices have been marketed, it is apparent that certain shortcomings are inherently in the alluded to devices which could conceivably account for their nonuse, or for such limited use that the devices have not come to my attention.